Phonograph-reproducer.



A. L. BURKE. FEONOGRAPH REPRODUOER. APPLIOATION'IILED APBA, 1913.

[/1 09/7 for: .flfimiam Z. 3 1/346 Patented June 17, 1913.

ABRAHAM L. BURKE, or CHICAGO, ILL

INOIS, ASSIGNOR TO WALTER A. SCOTT,

TRUSTEE.

PHON-O GRAPH-REPRODUCER.

Specification of Letters Patent.

Patented June 17, 1 913.

Application filed April 4, 1913. Serial No. 758,827.

To a]! whom, 2'25 may concern 'Be it known that I, ABRAHAM L. BURKE, acitizen of the United States, residing at Chicago, in the county of(look and State of Illinois, have invented certain new and usefulImprovements in Phonograph-Iteproducers, of which the following is aspecification.

The object of my invention is to improve the construction of phonographreproducers in such manner as to make the reproduced sound more pleasingand a more faithful reproduction of the original sound.

As is well known the reproduction of sounds by phonographs is ordinarilymade up in part of extraneous sounds not forming part of the originalsounds recorded upon the phonograph record, and all sounds are notreproduced with the same proportionate value which they have in theoriginal. These extraneous sounds may arise from a variety ofcauses, butin all cases they have an injurious effect upon the faithfulness of thereproduction and they are invariably of a disagreeable character. I havefound that these extraneous sounds can be largely eliminated and thetone of the reproduced sounds greatly improved by the constructionherein described and claimed and illustrated in the drawings, in whichFigure 1 is a cross sectional view of a phonograph reproducer of a typenow in common use, but having my improvements applied thereto. Fig. 2 isa view of the reproducer box from the side'on which the needle arm islocated. Fig. 3 is a detail perspective View of my improved reproducerarm; and Fig. 4 is a cross sectional view through the end of thercproducer arm adjacent the needlesocket. Fig. 5 is a bottom plan viewof the sound box.

In phonograph reproducers, as ordinarily constructed, the needle arm isan all-metal member extending from the point of attachment to thediaphragm to the point of attachment to the reproducer needle. Ac-

cording to my invention I break the allmetal path between the diaphragmand the needle by the interposition in said path of some substanceditlerent from the metal of which the needle arms have heretofore beenformed, the object being to provide a construction of such a characteras to eliminate the obnoxious sounds produced by an allmetal needle armand to improve the tone of the reproduced sound. A convenient means ofbringing about the desired result is to construct the needle arm of theform shown in the drawings. The outer end 1 of the needle arm there.shown is formed of metal secured to thediaphragm 2 by means of a screw3 in the usual manner, the end of the needle arm and the screw beingfurther held to the diaphragm by means of wax or other adhesive 4. Theouter metallic end 1 of the needle arm does not extend continuously tothe inner end thereof, but is secured to an intermediate part 5 of someother material, the intermediate part 5 being in turn secured to theinner metallic part 6 of the needle arm. In practice, I have foundcelluloid to be a material well adapted to eliminate the undesirablevibrations and to correctly reproduce the sounds. In the form of myinvention shown in the drawings, I interpose celluloid between thediaphragm and the needle. A convenient mode of assembling the structure,a mode which I have used in practice, consists in constructing theintermediate part of the needle arm of two layers 5'", 5" of celluloid,the thicker part 5 being grooved at its opposite ends to receive theouter and inner metallic parts 1 and 6 of the needle arm after which thethinner celluloid layer 5 is secured to the part 5' and the metallicouter and inner parts 1* and 6 of the needle arm are firmly secured inplace by means of rivets 7 passing therethrough and through thecelluloid.

My invention is in nowise restricted to the specific constructiondescribed, although I have found such'construction well adapted to thepurpose intended.

Together with my improved needle arm I use certain other improvementswhich coact therewith in improving the quality of the reproduced sound.Beneaththe heads of the screws 8, whereby the needle arm'is securedagainst its knife edge bearings 9, I insert Washers 10 formed of rubberor other more or less soft and yielding material, these washers havingthe effect of preventing the transmission of vibration from the needlearm to the casing of the diaphragm.

A further improvmnent which I find to have a beneficial effect inconnection with the other improvements herein described is the use ofhard celluloid gaskets 12 between ,7

thereby obviates the injurious effect upon 1 the tones which I havefound to be caused by the soft rubber gaskets. able that the improvementin by the use of the hard celluloid gaskets may be due to their havingthe effect of doing 1 away with the dampening of the vibrations in thediaphragm by thecontact therewith of the soft rubber gaskets, and itseems probable that the hard celluloid gaskets which directly contactwith the diaphragm do not lessen its effective diameter, as is done bythe direct contact of soft rubber gaskets. However this may be I havefound in prac tice that a material improvement in tone is brought aboutby the use of the hard celluloid gaskets, and that the use in eo1nbination of my improved needle arm, the hard celluloid gaskets, and thewashers beneath the heads of the screws, which hold the needle arm inplace brings about a great improvement in the tone of phonographs, in

It seems probtone caused 1 iparts of metal and of celluloid, throughsome cases imparting a pleasing and true 5 tone to phonographs whichwithout my 1m- Lprovements give only an unpleasant and lunfaithfulreproduction of the original sound.

I claim:

1. In a phonograph, a diaphragm, and a needle arm,

which the vibrations are transmitted.

2. In a phonograph, a diaphragm, a needle arm, said needle armcomprising a metallic outer part secured to said diaphragm, a celluloidmtermedlate part secured to said outer part, and a metallic inner partsecured to said intermediate part.

3. In a phonograph, a dlaphragm, and a needle arm, said needle armcomprising a celluloid portion through which the vibrations aretransmitted.

In testimony whereof, I have subscribed ABRAHAM L. BURKE.

my name.

said needle arm comprlslng

